A process of electropolish is to connect a workpiece to an anode and a metal to a cathode, then the whole structure including the workpiece is put into a electrolyte and electrified with a direct current. The defects on workpiece surface are removed and the surface is then shinny and smooth. Features of electropolish are for improving surface cleanness, roughness, passivation, etc. For different fields of semiconductor, chemical industry, biochemical engineering, foodstuff industry, tubes are required to deliver fluids of those fields, and inner surfaces of those tubes are treated by polish or electrolysis for cleanness and anti-corrosion. Especially, products of IC/LCD/III-V require high standards of cleanness and anti-corrosion.
In prior arts of U.S. Pat. Nos. 4,826,582 and 4,849,084, which electropolish a 10-meter heat exchange tube, teach an electrode device for positioning a workpiece and sealing an electrolyte. The prior arts adopt a 3-layer structure for delivering the electrolyte with high pressure air, but said structure is complicated and only suitable for bigger diameter workpieces, not for diameters under 3 cm.
Prior art of U.S. Pat. No. 5,958,195 teaches the technology of electrolyzing and polishing an inner surface of a long and bended tube. However, to electrolyze and polish a bended tube, an electrode must move alone a bended curve without a short circuit. The most important parts are a flexible electrode and an insulation device. The insulation device is to avoid the short circuit and non-concentricity, but it blocks electrolyte flowing and makes a non-uniform electric field, etc.
Prior arts of U.S. Pat. Nos. 4,601,802 and 4,705,611 offer a fixture applied inside a tube, and the fixture stabilizes a plurality of axially rotating tubes simultaneously. An end connector can circulate tube and exhaust gas from an upper end, and the electrolyte can be recycled after overflowing. An electrode length is equal to the tube's length, therefore a huge space and a super power supplier are needed to fit such conditions.
Based on the aforesaid issues, the inventor of the present invention has being studied and referred to practical experiences and theory for designing and effectively improving the prior arts.